The Public Domain refers to works for which the copyright has expired (pre January 1, 1923), the copyright holder has placed in the public domain through a special license, and in certain other cases. These works can be used in any manner without permission.
Here are some good places to find Public Domain resources:
Digital Public Library of America (DPLA) Primary Source Sets
- Primary source collections grouped by topic including history, literature, and culture. Discover photos, letters, sound recordings, advertising, posters, and more.
Library of Congress Prints and Photographs
- Access the wide collection of the LOC. Check the copyright permissions for each image for details.
NASA Images
- Some images are copyrighted and some are free to use. Check each photo for information.
National Gallery of Art
- Images from the National Gallery of Art which can be downloaded and shared.
Pixabay
- Find creative commons licensed images to reuse.
Smithsonian Libraries
- Discover online art, books, photos, and more from the Smithsonian collections.